Really weird.... Was it "popping" from the start or not?
Since this is a Single rail PSU, you have 2 polarities, + and - so you can't be wrong ( PSU + to Module +, PSU - to Module -)
That’s what I thought about the wiring! Just second guessing myself. I also cleaned up the wiring and properly grounded the case.
it’s popped from the first time I powered it up. It’s two quick pop-pop sounds, not like an old school solid state amp thump.
I don’t think it has a mute pin, just fault, clip otw, reset, and ground.
bawth I have same module and the pop is barely audible. I've been running 48V for 2 years without problem so its not the voltage. Seems like theres some wrong with your anti pop circuit or do you brake the signal chain with an input signal selector somewhere? On a separate note I would also advice you to shorten the psu cables between psu and amp. The extra impedance there does you no favour in class D..
Daniboun. I just finished modding the same tpa3255 board. It looks like it has 10kOhm in the feedback loop and when I changed that to 1kOhm the sound got so much better and dynamic! The gain got much lower of course so I also changed the two input resistors. I saw no reason for the 10kOhm signal series resistor to be that high so I lowered it to 500ohm since that was what I had lying around to get some gain back. The board really came to life with more feedback. The hiss is also very low and in general I'm very happy with this dirt cheap board 
My 3EAUDIO TPA3255 rev.A has started to pop on the left channel when I turn it on. The pop is very quiet. It did lose a bit of volume in that channel for a couple of days then went back to normal. Not sure what is going on, I could not find any loose connections so something might be breaking down. It has some mods, bypassed opamps and Panasonic caps.
I have ordered a rev.b and plan on bypassing the opamps again and try some Vishay caps 50v 470uf MAL213651471E3.
I did consider 2 mono tpa3255 boards but did not want to spend that much. I did find an amazing case that I might get in the future, a QUAD405 clone on aliexpress.com for about £100.
I have stopped using a RaspberryPi, Volumio and Balanced DAC as it lacked the inputs I wanted (sound Q was good). I got myself for Xmas a NAD C685 preamp, with Dirac room correction and really like it. Except for the pop and the temporary loss in volume the rev.A has no hisses or hums and sounds excellent so I will keep it as a spare.
I never got my AKITA all-in-one Amp group buy
I have ordered a rev.b and plan on bypassing the opamps again and try some Vishay caps 50v 470uf MAL213651471E3.
I did consider 2 mono tpa3255 boards but did not want to spend that much. I did find an amazing case that I might get in the future, a QUAD405 clone on aliexpress.com for about £100.
I have stopped using a RaspberryPi, Volumio and Balanced DAC as it lacked the inputs I wanted (sound Q was good). I got myself for Xmas a NAD C685 preamp, with Dirac room correction and really like it. Except for the pop and the temporary loss in volume the rev.A has no hisses or hums and sounds excellent so I will keep it as a spare.
I never got my AKITA all-in-one Amp group buy
Hello everyone
I have a tpa3255 shui yuan audio board and something strange happened with it.
I will describe it chronologically, maybe it will be easier to diagnose or maybe someone had the same case.
I bought it on Amazon, when it arrived I connected the power from the 40V li-lon battery, connected the cheap test speakers, the signal from the DAC and left it for 100h checking and warming up.
After 100 hours without any failure or burning of the speakers, I connected it to my main listening speakers. It sounded surprisingly well for such a small thing.
I planned to upgrade capacitors, coils and an op-amp and raise the PWM frequency to 600kHz. When all the parts arrived, I started testing:
-I connected the oscilloscope and checked what noise is at the output and what the music signal looks like at the output.
Noise was absolutely minimal, the musical signal had visible steps.
-Then I soldered the Freq_adj resistor from 30k to 10k to get PWM 600kHz.
-I checked what came out on the oscilloscope - the noise is still low, the music signal has smaller steps - I think it's better.
-During the tests, I had a laptop connected as the signal source. Unfortunately, my laptop has a problem that sometimes when I click on a track to play it makes a loud pop when it starts up. Several times this happened, loud crackled loudspeakers (loudspeakers did not burn) and the shui yuan audio board entered fault mode several times and required a reset.
-After these few fault modes, a constant sine wave of about 100kHz and 300mV appeared at the amplifier output.
-When this sine wave appeared, the only modification of the board was the change of the PWM frequency from 450kHz to 600kHz and the replacement of some power capacitors.
I sit on it for a few days and I can't find the reason. Currently, I replaced the inverter XL7015E1 with a linear power supply for LT317 12V, replaced the 1uF SMD capacitors on PVDD_x gates, replaced the 1uF capacitors behind the coils, added 0.1uF on the op-amp power feet. The amplifier is powered by a 40V battery, so it is not a derivative of the power supply. Unfortunately, the sine wave at the output is still the same.
Is it possible that entering TPA3255 into Fault mode causes some damage to it and therefore I have a sinusoide on the output ???
Theoretically, the TPA3255 chip has implemented security measures that prevent it from being damaged.
I read on other forums that these amplifiers have noise and PWM residues on the output, but my board did not have it, it only happened after the unfortunate connection of the laptop, clicks and the Fault mode
Maybe other elements have been damaged? Eg BST_x gate charging capacitors 33nF? I don't know how to check them. I checked with the meter and there are strange voltages, e.g. 83V, 93V, 100V.
Or 10uH coils? Is it possible?
Generally the amplifier works, plays music normally. Despite this sine wave at the output visible on the oscilloscope, I do not hear any distortions or noise in the speakers.
Voltage:
PVDD 40V,
GVDD and Vdd 12V,
DVDD 3.29V,
AVDD 7.76V (when reset: 0V),
VBG 1.2V,
Freq_adj 0.81V (10k resistor).
on the speaker terminals is 19V measured to power ground.
I will be grateful for any hints.
ps. video with music signal before and currently https://drive.google.com/drive/folders/1I13ixqKM0AvhuF9zSr293BRaTzRYy0aK?usp=sharing
I have a tpa3255 shui yuan audio board and something strange happened with it.
I will describe it chronologically, maybe it will be easier to diagnose or maybe someone had the same case.
I bought it on Amazon, when it arrived I connected the power from the 40V li-lon battery, connected the cheap test speakers, the signal from the DAC and left it for 100h checking and warming up.
After 100 hours without any failure or burning of the speakers, I connected it to my main listening speakers. It sounded surprisingly well for such a small thing.
I planned to upgrade capacitors, coils and an op-amp and raise the PWM frequency to 600kHz. When all the parts arrived, I started testing:
-I connected the oscilloscope and checked what noise is at the output and what the music signal looks like at the output.
Noise was absolutely minimal, the musical signal had visible steps.
-Then I soldered the Freq_adj resistor from 30k to 10k to get PWM 600kHz.
-I checked what came out on the oscilloscope - the noise is still low, the music signal has smaller steps - I think it's better.
-During the tests, I had a laptop connected as the signal source. Unfortunately, my laptop has a problem that sometimes when I click on a track to play it makes a loud pop when it starts up. Several times this happened, loud crackled loudspeakers (loudspeakers did not burn) and the shui yuan audio board entered fault mode several times and required a reset.
-After these few fault modes, a constant sine wave of about 100kHz and 300mV appeared at the amplifier output.
-When this sine wave appeared, the only modification of the board was the change of the PWM frequency from 450kHz to 600kHz and the replacement of some power capacitors.
I sit on it for a few days and I can't find the reason. Currently, I replaced the inverter XL7015E1 with a linear power supply for LT317 12V, replaced the 1uF SMD capacitors on PVDD_x gates, replaced the 1uF capacitors behind the coils, added 0.1uF on the op-amp power feet. The amplifier is powered by a 40V battery, so it is not a derivative of the power supply. Unfortunately, the sine wave at the output is still the same.
Is it possible that entering TPA3255 into Fault mode causes some damage to it and therefore I have a sinusoide on the output ???
Theoretically, the TPA3255 chip has implemented security measures that prevent it from being damaged.
I read on other forums that these amplifiers have noise and PWM residues on the output, but my board did not have it, it only happened after the unfortunate connection of the laptop, clicks and the Fault mode
Maybe other elements have been damaged? Eg BST_x gate charging capacitors 33nF? I don't know how to check them. I checked with the meter and there are strange voltages, e.g. 83V, 93V, 100V.
Or 10uH coils? Is it possible?
Generally the amplifier works, plays music normally. Despite this sine wave at the output visible on the oscilloscope, I do not hear any distortions or noise in the speakers.
Voltage:
PVDD 40V,
GVDD and Vdd 12V,
DVDD 3.29V,
AVDD 7.76V (when reset: 0V),
VBG 1.2V,
Freq_adj 0.81V (10k resistor).
on the speaker terminals is 19V measured to power ground.
I will be grateful for any hints.
ps. video with music signal before and currently https://drive.google.com/drive/folders/1I13ixqKM0AvhuF9zSr293BRaTzRYy0aK?usp=sharing
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Hi everyone! I'm an electronics student from Umeå (Sweden) and I'm currently planning out a project in a PCB course that I'm taking. I'm really excited because I'm allowed to build an amplifier with the TPA3255!! The only downside is that (as you probalby know... ) they are not available on Digi-key, Mouser or anywhere else. So I was thinking, since I have access to a soldering lab, that I could buy a used amplifier and take the chip from there. Buuut, I can't find a used amplifier either...
So I'm wondering if anyone has any tips for me regarding finding a TPA3255 or a suitable replacement. I'm aiming for a stereo class D amplifier that could deliver ~100W into 8Ohms with a THD+N < 1% and an SNR > 115dB. I know these are some difficult goals to reach, but TI has two great papers that I've read on output LP-filters and PFFB for the TPA3255, which is why I choose this IC. It will probably still be difficult, but aim for the stars and land on the moon! An option could also be to find a less powerfull IC and build a dual monoblock amplifier with the IC in a PBTL configuration.
I'm thankfull for any tips I can get!!
PS. It's hard to be a student when you can't find any parts :'(
So I'm wondering if anyone has any tips for me regarding finding a TPA3255 or a suitable replacement. I'm aiming for a stereo class D amplifier that could deliver ~100W into 8Ohms with a THD+N < 1% and an SNR > 115dB. I know these are some difficult goals to reach, but TI has two great papers that I've read on output LP-filters and PFFB for the TPA3255, which is why I choose this IC. It will probably still be difficult, but aim for the stars and land on the moon! An option could also be to find a less powerfull IC and build a dual monoblock amplifier with the IC in a PBTL configuration.
I'm thankfull for any tips I can get!!
PS. It's hard to be a student when you can't find any parts :'(
Hi,
Mouser have in stock TPA3244 which are lower power than TPA3255.
Regards,
Shadders.
Thanks Shadders! I looked at the datasheet and it's a good option! But the datasheet doesn't seem to supply all of the measurements for an 8Ohm load and my professor always tells me "If the measurement isn't in the datasheet, it's probably not any good" lol. I'm pretty sure it will work just fine tho, as long as I get a good Q-value in LP-filter for an 8Ohm load.
This was a really interesting option!!
Going the discrete route wasn't really my plan, but this seems doable! Do you know of any good articles or papers on discrete class D that i coudl read??
Thanks again!!
Hi,
The TPA3244 does have 8ohm load THD figures which exceed the 4ohm load. Page 10 for the BTL implementation shows this.
Regards,
Shadders.
Hi,
Here is a link to the UM10155 Philips design :
http://www.handsontec.com/pdf_files/UM10155_2_Discrete_ClassD_Amp.pdf
Regards,
Shadders.
Yes, you're right! But there are not any for a PBTL configuration, which I would use in a dual monoblock design. From what I can find elsewhere it seems that 8 ohm loads and a PBTL configuration is unusual. Again, with the right LP-filter it would probably work just fine, but do you know if it will affect audio quality? Also, I'm guessing PBTL and 8 Ohm loads is a bit inefficient - is this true?